Darwin Day is an annual, international commemoration of the birthday and ideas of Charles Darwin, a British naturalist born February 12, 1809, and author of the seminal book On the Origin of Species by Means of Natural Selection.

The first organized Darwin Day events took place in 1995, and were organized by the Humanist Community of Palo Alto, California. The years since have seen Darwin Day celebrations around the world increasing annually on a steady scale.

In 2006, the Paleontological Research Institution and its Museum of the Earth, in collaboration with Cornell University and Ithaca College, celebrated the first official Darwin Day in Ithaca, New York, with a five-day series of panel discussions, film screenings, speakers, and workshops, aimed at increasing awareness of Darwin’s theory and its relevance today, in the Ithaca community and beyond.